[QUERY] EventHub Throttle and TU relationship / Latency details / Partition and TU relationship

Query/Question

I’ve multiple queries:

• 1 TU is 1 MB / sec or 1000 msgs / sec (I read it somewhere written as 1000 API calls / sec) whichever happens first. Imagine I’ve message of size 500 bytes, then I would be able to create an EventDataBatch containing ~2000 msgs (less than 2000 but close to it) and I would be able to send it to EventHub with 1 send call eventProducerClient.send(eventDataBatch). In this case, the size of eventDataBatch will be ~ 1MB (less than 1 MB but close to it) and I am making 1 API call (but sending ~2000 msgs in that call). Will my request be throttled?

  Or put in another way, If I know that my per message size is < 1 KB, should I still limit the eventDataBatch to only 1000 messages (and utilizing only half of 1MB / sec)?

  And if the requests are being throttled, how is the application supposed to know about this? There is only a WARNING log. I raised the relevant BUG here: https://github.com/Azure/azure-sdk-for-java/issues/11003

• Is there a way to know the time EventHub SDK takes to push my Event (or EventDataBatch) to EventHub? I currently have no latency information from SDK. I am calculating it in my own code right now like this:

    try (com.codahale.metrics.Timer.Context ignored = latency.time()) { // dependency io.dropwizard.metrics:metrics-graphite:4.1.7
        eventHubProducerClient.send(eventDataBatch);
    }
  

  Is this how this is supposed to be done? Also, what is the expected latency while pushing data (one Event / EventDataBatch) to EH?

• I am trying out EventHub SDK Consumer and Producer in a sample application where I consumer from an EventHub A (having 32 partitions, loads of data available, reading from EventPosition.earliest() and not storing checkpoints) and pushing the messages unmodified to another EventHub B having 5 partitions. Since each partition can only be maxed out with 1 TU, it should be pointless to have more than 5 TU on EventHub B. However, if I enable Auto-Inflate (with max TU allowed at 20) and keep my Consumer and Producer running, it inflates my EventHub to 20 TU and I can see significant gain in performance (more than double than keeping TU at 5).

  I am not able to understand this because no partition can utilize the 15 extra TU that are being allocated by Auto-Inflate feature. Just to point it out EventHub B is the only EventHub in that namespace. So the producer EventHub namespace overall only has 5 partitions.

Why is this not a Bug or a feature Request? I couldn’t categorize it as bug / feature request because I might be missing a few details in my understanding.

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[serkantkaraca]

@shubhambhattar, so we are good to close this issue and track the new issue only?

[serkantkaraca]

@shubhambhattar, thanks for providing new test data. Can you send me your test namespace so I can check service side metrics and failures? You can reach me from [e-mail]